Gear-tooth gauge



J. A. MCINTOSH GEAR TOOTH GAUGE Sept. 13; 1927 1,642,077

Filed June 19, 1920 2 Sheets-Sheet l (fez neg Sept. 13, 1927.

J. A. M INTOSH GEAR TOOTH GAUGE Filed June 19, 1920 2 Sheets-Sheet 2Patented Sept. 13, 1927.

UNI ED STATES "PATENT OFFICE.

JAMES A. HOIli'I-OSK, OF lJETBOIT, MICHIGAN, ASSIGNOR TO THELEES-BBADNEB COMPANY, 01 CLEVELAND, OHIO, A OORPOBATIONOF OHIO.

GEAR-TOOTH GAUGE.

This invention relates to gauges for indicating the condition of gearteeth being cut. At the present time, in setting up a machine forcutting gear teeth, it is the practice to 6 cut a gear and then roll thegear into contact with another gear and solely by observation and feeldetermine whether t e teeth are accurately and properly cut to get theproper meshing action between the teeth of 10 the two gears. It is theprinci al ob ect of the present invention to provi e an instrument whichwill register any inaccuracies by thousandths of an inch or less, in agear 5' which is not out true.

In the drawings,-

\ Fig. 1 is a plan view of the instrument.

Fig. 2 is a side elevation of the. same,

partly in section. I

Fig. 3 is a sectlon on the line 3-3 of Fig. 2.

a designates a base that may be bolted thru the slot 6 to a suitable-suport. This base is recessed to form a sli e-wav a: in which travels theslide 0 actuated by the winged screw d against the resistance of. thespring e. This slide is provided with an upstanding post f-which'ournals a reel g adapted to take a steel and h fastened thereto b theclamping block i. The

center (considered in the direction of its thickness) of this band uponthis reel registers substantially with the pitch circle of the gear.which is bolted to the externallythrea ed hub y of the reel by means ofthe 85 nut in. The op osite end of the band h is clamped to the d by theblock m. A torsional spring n has one leglattached to the slide 0 andthe other to t e reel g. (See Fig. 2.) This keeps'the reel turned todraw 40 the band taut at all times. The object of this band is to causethe gear 7' to so' rotate, when the slide 0 is moved inwardly againstthe tension of the spring 0, that it will develop its pitch circle intoa straight line.

At 9 is shown a major slide adapted to be adjustably slid in ways H inthe base a. The position of the slide 9 in the ways may be fixed byscrews f-q. The slide 9 carries supports o -0 provided with rectangularldeways oo'* in which is mounted for sliding movement transversely ofthe slide g, a minor slide 0, provid with a 1920. Serial No. 390,089.

point or projection p. The point p is shaped like a rack tooth andmeshes with the teeth of the gear A lever 2,'-pivotally supported on thesli e g at 2 has one end in engagement with a notch z in the minor slide0 and has the other and longer end in engagement w1th the stem .1 of anindicator 2, such as a Brown & Sharp indicator or any similar device. Acentralizing mechanis'm is provided for normally maintaining the lever zand minor slide 0 in a central positlon and comprises a guide rod t suported on posts u-a, a sleeve 8 loosely sli dable on the guide rod, andsprin s v'v between the ends of the sleeve 8 an the osts w-u. The lever.2 is pivoted to the s eeve When the gear 7' is rotated as abovedescrlbed, the teeth of the gear will mesh with the point p similarly asit would if it were one of the teeth of a rack.

The operation will be (perfectly plain. When the gear j to be testeismounted on the post f, the slide 0 and the adjustable slide q arepreferably in the positions shown in Fig. 1, so that the point p mesheswith the gear teeth. Before the nut is tightened, the gear 1' is turnedby hand counter clockwise until one of its teeth is in engagement orcontactwith the surface p of the point p, this contact being resilientlymaintained by the centralizing mechanism above described, as will beunderstood. Now, by turning the screw d .in one direction, the slide ais caused to move forward, the spring e taking up any lost motion. Thisunwinds the band h from the reel, causing the gear jto roll in the sameway it would roll if it were rolling on a plain surface on its pitchcircle, this operation serving to ut thettorsional s ring- 11. undertension so t at it maintains t e band It taut as rolling of the reel andunwinding of the band takes place. When the screw d is turned intheother direction, the slide 0 is thereby moved back towards its startingposition, and the torsion spring 7 rotates the reel 9 and gear in theopposite direction and thus takes up any slack in the band h which wouldotherwise occur therein. This is the movement the gear would take intraveling over a rack havin teeth accurately cut. Instead of travelingover a rack, t

e teeth travel over the point p connected with the indicating lever.Since the surface p of the point or tooth p is held in contact with theadjacent tooth face as above described, the point or 5 tooth 79 will bemoved if the tooth face is inaccurate, and such movement will cause thelever z to rockand the amount of its movement will be registered onthe(hill of the indicator 2, thus indicating in fractions of an inch theamount of inaccuracy in the gear tooth face. In this way one face ofeach tooth, one after another, can be tested. Then by loosening the nut11 and rotating the gear clockwise until the other surface 4* of thepoint or tooth 72 is engaged by the much better running of the machinerycontaining sets of gears. I

There are several well recognized circles in connection with calculatinggears; for in stance, there is an addendum circle, a, root circle andany number of pitch circles the diameters of which do end upon the slopeor pressure angle of th surfaces (in this case the surfaces 7) and pwith which the gear to be tested is meshed. It will be obvious that myinstrument, especially the band,

could be used to develop any one of these circles by simply changing thereel to accord with such circle. Hence I am not limiting myself in theclaims directed to the specific means for developing a itch circle to asintill till

gle circle. I have, there ore, seen fit to refer to such a circlegenerically as one of the gear teeth circles. i

What I claim is:

l. In a machine for the purpose specified, the combination of a gearsupport, means for causing a gear on said support to roll and develop apart of its pitch circle into a straight line, and testing meansincluding a device yieldingly sup orted at the side of the tooth to hetested an in engagement therewith, so that, when the gear tooth isaccurately out, the said means will not be to any appreciable extentdisplaced when the gear is caused to roll over the same in do velopingits said pitch circle, but, when the gear tooth is inaccurately formed,the same will be displaced from its normal position.

2. In a device for the purpose specified, the combination of means forsup orting a gear and causing it to roll and evelo a part of its pitchcircle out in a straight lme, a. testing tooth, means for yieldinglysupporting said tooth in a predetermined position with one face thereofadjacent to the face of a gear tooth of a gear on said supporting meansso that, if the latter is accurately shaped, the said testing tooth willnot. be a preclabl displaced when the gear tooth rolls over the same asthe gear develops its pitch circle, but, when the gear tooth isinaccurately formed, the same will be displaced from its redeterminedposition, and means actuated y said testing tooth for indicating suchdisplacement of the gear tooth.

3. In a device of the character described, the combination of means forsup orting a gear and causing it to roll and evelop a portion of itspitch circle into a straight lmo, a tooth in the form of a'rack tooth,means for yicldably supporting said tooth in a. predetermined positionwith one face thereof adjacent a gear tooth of a ear on said supportingmeans, so that wien the latter is accurately formed it will roll overthe rack tooth without appreciably displacing the same when the geardevelops its pitch circle into a straight line, but, when the gear toothis inaccurately formed, the said rack tooth will be displaced, andindicating means to show the displacement of said rack tooth.

4. In an instrument of the character specitied, the combinationof meansfor supporting and rolling a gear to cause it to develop a art of itspitch circle into a straight line, a ever, resilient means foryieldingly holding the lever in a normal position, a pointed memberconnected with the lever, and adapted to mesh with the teeth of a gearon the supporting means in developing its pitch circ e into a straightline whereby any irregularities in the teeth cause the lever to move toindicate the presence of such irregularities.

5. In an instrument of the character specified, the combination of asupport, means for developing a portion of the pitch circle of a gearsupported on said support into a straight line, a member adapted to meshwith said gear, a lever pivotally mounted on said support andoperatively connected to said member, means for holding said lever in apredetermined position, and an indicator engaging the other end of thelover to indicate any irregularities in the gear teeth actuated by theirregular teeth of the gear in displacing said lever.

6. In. an instrument for the purpose specified, the combination of asupport, means for causing a gear supported on said support to develop aportion of its pitch circle into a straight line, a member adapted toengage between the teeth of the gear in making such movement, anindicating lever pivotally mounted on said support, means for yieldablyholding said lever in a predetermined position, and an indicatorengaging the other end of the indicating lever in a relation to multiplythe movement from the point to the indicator stem contact whereby pullthe an irregularities in the gear teeth cause the in icating lever tomove and multiply the movement and communicate the same to the saidindicator,

{7. In an-instrument for the purpose specified, the combination ofindicating means for testing gear teeth for irregularities, and meansfor supporting a ear to be tested and causin it to roll and evelo aportion of one 0 its gear teeth circles mto a"straight line, thelattercomprising a slide .on which the gear is mounted rotatably, a reelconcentric with the gear, and a band fixed to the reel periphery inregistry with said circle of the gear and ada ted to-unwind as the slideis caused to trave and thereby constrain the gear to develop its saidcircle into a straight 8. In an instrument for the purpose speci-v fied,the combination .of indicating means for testing gear teeth forirregularities, and means for supporting a gear to be tested anddeveloping a portion of one of its teeth circles-into a straight line,and comprising a slide, a reel rotatably mounted on the slide andarranged to be secured to the gear to be tested, a band carried on thereel, the band, the reel and the gear being arranged so that the reelperiphery is in registry with the said *circle of the gear wherebymovement of the slide causes the gear to develop itssaid circle into astraight line to permit the operation of the tooth testing means.

9. In an mstrumentjor the purpose specified, the combination of a slide,a reel mounted on the slide, a band fixed onto the reel and windingabout the periphery of the reel, the band being arranged to be insubstantial registry with one of the gear teeth circles of a gear to betested adapted to be secured to and in registry with the said reel, anda spring for operating upon the reel to band taut about the reelperiphery.

10. In an instrument for the; purpose specified, the combination ofindicating means for testing gear teeth for irregularities, and

means for supportmg a gear and causing it to develop a portion of one ofits gear teeth circles into a straight line, the latter comprising aslide adapted to gupport said gear, means for advancing the slide, areel rotatably mounted upon the slide, a band encircling a portion ofthe periphery of the reel and having one end fixed, and atorsionalspring for taking up the slack of the band on the reel, thesaid band being in substantial registry with the said circle of saidgear.

11. In apparatus of the character described, the combination of asupport, a stud mounted thereon and supporting a roller and adapted tosupport a gear to be tested, a flexible member connected to said supportand roller, means for moving ported on said stud to effect winding ofand 'for translating and rotating a gear on sai a gear sup:

flexible, member on and oil said roller, a lever, lever operatingconnections between a toothofv the gear at one end of the'leve'r,

and means. operated bythe movement of said lever to indicate theinaccuracies of the gear teeth.

12. In apparatus of the character de-- .scribed, the combination of a suport for a gear permittmg a, gear su porte thereon to \be translated androtate .a separate support associated w th said first mentioned support,a tooth engaging member mounted to move on said separate support in adirection parallel to the translatory movement of the gear, andindicating means operatively connected with said tooth engaging memberto indicate the amount-of movement thereof resulting from inaccuraciesinthe gear teeth.

In apparatus of the character described, the combination of a sup ortfor a gear, an ind1cating means on em support, a tooth engaging membermovably mounted on said sup ort and actuated by inaccuracies in the teetof a gear on said support, guide means permitting translator movement ofthe gear in a direction paral el to the direction of movement of saidtooth engaging member and rotary movement about its axis, and operativeconnections between said tooth engaging member and said indicatingmeans.

14. In apparatus of the class described,

the combination of a support for a gear to be tested, means associatedwith the support support, a separate support associated with sand firstmentioned support, a gear tooth engagmg member on said separate sup ortmounted for movement in a straight me,

and indicating means operatively connected with said tooth engagingmember to indicate the movement thereof resulting from inaccuracies inthe gear tooth.

15. In a device of the class described, means for supporting a gear andcausing it to roll and to develop a portion of its pitch circle inastraight line, a movable contact device supported and constrained tomove in ioo a straight line, and means for holding said device inyieldable engagement with the face of a tooth of a gear on the support,whereby, when the gear tooth face is accurately formed, the gear willroll without appreciably moving the contact device, but,

when the gear tooth face is inaccurately 1 formed, the device will bemoved, and means for indicating the movement of said device.

16. In apparatus of the class described, means for supporting a gearwhich is 'to be tested and causin it to roll on its pitch circle withoutslipping, a testing member pro-- vided with a surface having the shapeand position relative to a gear on the supporting means of a rack toothface in meshed engagement with a tooth of the rolling gear,

the testing member bein supported with ing the testing member, but, whenthe gear said surface held yieldab in engagement tooth is inaccuratelyformed. will move it with a tooth face of the supported gear and andmeans for indicating the movement 0 10 movable in a direction paralleltothe move said testing member.

5 ment of the center of the gear when rolling, In testimony whereof Iaflix my signature.

whereby when the gear tooth is accurately formed, it'will roll withoutappreciably mov- JAMES A. MoINTOSI-L

